TFA was decent. By the time TRoS came around, Rian had taken the story in a different direction and left JJ to pick up the pieces. If there was a consistent storyline planned from the start, things could have been much better.
TFA was only decent because it had the exact same story structure as ANH.
JJ is someone who is good at selling his ideas, he's just not very good at executing them. This started before he was handed the reigns of Star Wars (or Trek for that matter). Just look at the trajectory of Lost: everyone guessed the ultimate twist in season one so he had to spend 6 seasons pretending that that wasn't the twist he had planned.